Many microfabricated valves have been
proposed; however, proposed microvalves in general are
unsuitable for controlling flows at high pressures
(>20 atm) and cannot be used for high-pressure liquid
chromatography (HPLC), the most common technique used for separating
and analyzing chemicals.

We have developed techniques for
laser-fabricating fluoropolymer switches in microchannels
by photopolymerizing fluoroacrylate monomers with Nd:YAG lasers and projection optics.
Our
technique uniquely enables fabrication of microvalves that operate successfully
in the harsh
environment (high pressure, varying solvents) used for HPLC analysis.

Recent developments in high-pressure microvalves have allowed us to
demonstrate high-pressure injection of
subnanoliter volumes for HPLC analysis and explore miniaturized HPLC
separations and links to mass
spectrometry. We are interested, also, in other systems that require
high surface-area-to-volume ratios,
such as catalytic conversion of biofuels.